1. Field of the Invention
Exemplary aspects of the present invention relate to a development device and an image forming apparatus, and more particularly, to a development device and an image forming apparatus for stably and efficiently supplying developer to a developer carrier.
2. Description of the Related Art
Related-art image forming apparatuses, such as copiers, facsimile machines, printers, and multifunction devices having at least one of copying, printing, scanning, and facsimile functions, typically form a toner image on a recording material (e.g., a sheet) based on image data using electrophotography.
For example, when an electrostatic latent image is formed on a surface of a photoconductor, serving as an image carrier, a development device develops the electrostatic latent image with a developer (e.g., a two-component developer) into a visible toner image. The two-component developer includes toner and carrier. The development device stirs and disperses the toner and the carrier within the development device to charge the toner triboelectrically. Insufficient dispersal and charging of the toner may cause the toner to scatter from the development device, thereby generating a faulty image with background soiling or the like.
In particular, high-speed image forming apparatuses quickly circulate developer inside the development device, and are prone to causing insufficient toner charging. Increasing the capacity of the development device allows the toner to disperse more easily and charge sufficiently, but at the cost of an increase in the size of the development device and a concomitant increase in the overall size of the image forming apparatus.
To solve the above-described problem, various approaches have been taken.
For example, one related-art development device using two-component developer includes a development member and a developer agitation member separated from each other but connected by a developer circulation member. Another related-art development device uses a screw pump to transfer developer.
Such development devices include a developer carrier that holds developer, two screws to circulate the developer, a developer controller (such as a doctor blade), and the like. One screw supplies the developer to the development roller and the other screw collects the developer after development for possible reuse.
However, such circulation of the developer using screws tends to create an uneven supply of developer to the development roller, resulting in faulty images with uneven toner density.
Accordingly, there is a need for a technology capable of providing a development device for stably and effectively supplying developer to a developer carrier, and an image forming apparatus incorporating the development device for stably forming high-quality images.